In general, a performer, who plays various musical instruments, plays the instruments while seeing a score consisting of sheets having a predetermined size or a music book. It is generalized that such score is typically put and used on a music rack.
A variety of music racks are suggested and widely used. Among them, an example of music racks that are most widely used is shown in FIG. 1.
The music rack comprises a tripod-shaped support leg 1, which can be folded and rest easily on a ground, a strut 2 perpendicularly mounted to the support leg 1 and having a height capable of being regulated and a score bedplate 3 mounted to an upper end of the strut 2 and on which a score having a predetermined size is put.
In addition, since the strut 2 comprises pipes having sizes different from each other and mounted in a telescopic manner, its length can be changed. As shown in FIG. 2, a connection part of the pipes is fitted with a socket 4 to which a fixing knob 5 is screw-engaged, so that the strut can be fixed without a shake with its height being regulated.
Accordingly, when it is intended to regulate a height of the music rack, the fixing knob 5 is released and then the height of the strut 2 is changed in a telescopic manner. After that, the fixing knob 5 is again tightened, so that the height of the rack can be regulated.
However, the structure as described above has the problems that the fixing force is weak because the strut 5 can be fixed only with the tightening force of the fixing knob 5 and there can occur a scratch on a surface of the strut when the fixing knob 5 is strongly tightened.
In addition to the above problems, there are also other problems that an external appearance thereof is not good since the fixing knob 5 is protruded outwardly, and it is not possible to easily perform unfastening and tightening operations because the fixing knob 5 is small.
In the mean time, the applicant suggested a height regulating apparatus capable of regulating a height of a music rack just by pulling out or pushing a strut of the music rack with a physical force, so as to make up for the above problems.
The apparatus is suggested in a Korean Unexamined Utility Model Application No. 2003-22835 disclosing that a strut is comprised of pipe-shaped upper and lower members so that a length of the strut can be telescopically changed, the upper member is provided with a music bedplate, the lower member is provided with a tripod-shaped bedplate and fixing means for providing or releasing a fixing force by an elastic force of a spring is provided between the upper and lower members.
The fixing means comprises a fixing tube body that is engaged at a lower part of the upper member and thus widened to tightly contact to an inner diameter of the lower member or contracted, thereby providing or releasing the fixing force. The fixing tube body is provided with an operating body that is elastically mounted with a spring and thus contracts and expands the fixing tube body with physical rising and falling operations of a user.
Accordingly, it is possible to change a length of the strut just by pulling out or pushing in the upper and lower members of the strut using a physical force with the members being grasped by the user, so that the height of the music rack can be regulated conveniently and easily.
However, since the utility model disclosed has such a structure that the user should apply the elastic force of the spring with the physical force when regulating the length, it is needed much power, causing an inconvenience of a use. In addition, it is not easy to perform a minute regulation.
In addition, since the elastic force of the spring is gradually decreased when it is used for a long time, it is not possible to expect a smooth operation.